This invention is directed to a compact ion implantation system which has a separated ribbon beam ion source which has geometry which permits beam traverse across the wafer with minimum waste beam for maximum productivity and employs the same magnetic field for both the ion source and separator. The separated ribbon beam ion source is sufficiently compact that a plurality of such sources can be placed adjacent to each other for successive ion beam impingement on the same target or adjacent targets.
Prior ion implantation beams sources were comprised of separate functional components which were connected together to form the ion beam line. An ion source was used and it had its own magnetic field structure, if such was required, for the production of the ion beam. Ion separation downstream from the ion source required additional separation components. Due to the separate-element approach to the problems, the beam line is unnecessarily long and complex. These disadvantages are particularly difficult in the case of high current low energy beams because severe space charge expansion occurs in the region between the ion source and separator. Attempts to locate the separator just downstream of the ion source were unsuccessful because the magnetic fields interfered. That is, the axial magnetic field in the ion source was disturbed by the transverse magnetic field of the separator.
With the present close coupled, compact ion source, a small target chamber can be employed with several of the separated ion sources working on the same target or the same target wheel to provide higher ion dosage capability.
A suitable ion source is shown in U.S. Pat. No. 4,163,151.